Thomas Aquinas: Philosophy, Faith, and Reason
Thomas Aquinas: Philosophy, Faith, and Reason
Historical Context
St. Thomas Aquinas, a 13th-century thinker, lived during a period of European revival marked by growing towns, trade, and the rise of universities. Feudal society still prevailed, but the emergence of the bourgeoisie signaled societal change. This era witnessed the ideal of universal Christianity, influenced by cultural exchanges between Islam and Christianity, spurred by the Crusades and the Toledo School of Translators. The introduction of Aristotle’s works significantly impacted Western philosophy, shaping the development of scholasticism. Christian thinkers grappled with these works, including both the radical Averroist interpretations and the moderate versions reconciled with faith by Aquinas.
Influences and Impact
Aquinas was deeply influenced by Aristotle, adopting aspects of his ontology (theory of being, matter, and form), anthropology (body and soul), epistemology (knowledge through senses and abstraction), ethics (happiness as man’s end), and poetics (common good). Augustinian Platonism also influenced Aquinas, particularly in areas where Aristotelian philosophy clashed with Christian doctrine, such as the immortality of the soul. Aquinas drew upon earlier philosophers like Avicenna and Maimonides. His distinction between essence and existence originates from Avicenna, while the concept of natural law connects to Stoic philosophy. The Bible and Averroes (whose double truth doctrine and concept of the unity of the intellect Aquinas rejected) also played a role. Aquinas’s impact is evident in the Spanish scholastics of the 16th and 17th centuries and the concept of “natural law.” His thought, recognized as official Catholic doctrine, faced criticism from modern philosophers like Descartes and Kant, who opposed his ideas. His philosophy was even considered an obstacle to scientific progress.
Reason and Faith
Aquinas believed in a single truth attainable through reason and faith. Reason derives knowledge from sensory data, while faith relies on divine revelation. These two paths are independent. The truths of faith, exceeding human reason’s grasp, are studied by theology and accepted as divine emanations. Truths of reason, belonging to philosophy, are demonstrable through human intellect. Some truths, demonstrable by reason, are also revealed by God. In these cases, faith and reason merge (e.g., immortality and creation), and theology utilizes reason to understand truth (natural theology). Philosophy serves theology, and since truth is singular, philosophy and reason cannot contradict faith.
The Five Ways
One truth of faith amenable to rational argument is God’s existence. Aquinas offers five ways to demonstrate this, each sharing a structure: 1) starting from sensory experience, 2) applying the principle of causality, 3) rejecting an infinite causal series, and 4) concluding with an original being (God) as the source of the series. The five ways are: 1) Motion: from motion in the world to an unmoved mover, 2) Efficient Causality: from subordinate causes to an uncaused first cause, 3) Contingency: from contingent beings to a necessary being, 4) Degrees of Perfection: from degrees of perfection to an infinitely perfect being, and 5) Cosmic Order: from the order of the world to a first ordering intelligence.
Essence and Existence
To address creation, Aquinas distinguishes between essence (a being’s nature, its potential) and existence (its actuality). In God, essence and existence are identical; God’s nature necessitates existence. Other beings are contingent; their essence doesn’t necessitate existence, receiving it through God’s creative act.
Thematic Discussion and Justification
The primary theme is epistemological, as Aquinas explores how we understand reality. Ethics plays a secondary role, as the text explains human behavior in Aquinas’s time. The central idea is the relationship between faith and reason. Aquinas distinguishes them based on their content (faith focuses on articles of faith, reason on the natural world) and method (faith relies on revelation, reason on abstraction). However, some truths are accessible through both.
Aquinas rejects any contradiction between faith and reason. God authored both the natural world (accessible to reason) and the supernatural (accessible to faith). He rejects the Averroist idea of contradictory truths from different knowledge sources. Aquinas posits that faith supersedes reason when apparent contradictions arise, as faith, being divine revelation, is infallible. Reason, while not inherently deceptive, can be misused.
Aquinas identifies three types of truths: 1) those accessible only through faith (articles of faith, e.g., the Trinity), 2) those accessible only through reason (truths about the natural world), and 3) those accessible through both (preambles of faith, e.g., God’s existence). In the third type, faith and reason converge.
Regarding ethics, Aquinas believes happiness is humanity’s ultimate goal. Humans, endowed with intelligence, strive towards the universal good, which is God. This inherent orientation towards God forms the basis of human freedom in choosing among worldly goods. Free will underpins moral responsibility. Reason guides human behavior in exercising freedom. God, as the ultimate ruler, governs all reality through eternal law (lex aeterna), which is divine wisdom. From eternal law derives natural law (lex natura), humanity’s participation in eternal law. Humans are naturally inclined to act rationally, adhering to natural law, which aligns with eternal law. By following these laws, humans achieve happiness through contemplating God. This emphasizes intellect over will, contrasting with the Augustinian-Franciscan emphasis on love.